1998 Yamaha 115 hp 2 stroke - rpms rev up, but loss of power

[Lee Robinson]

When at low rpms everything is normal, but when I accellerate to take off it sounds like I hit a wave and my prop came out of the water as if I am cavitating...but I know that didn't happen. I backed off the trottle, looked at my guest, we both looked back and the motor, and then tried to take off again. The situation occurred again. We did this 2 or 3 more times and decided we better head back to the dock.

I have had the boat/motor for 2 years with no problems.

I took the prop off and the gears on the "prop axle shaft" that comes out of the lower unit where you mount the prop looks good there as well as the gears in the "prop hub." (The quotation marks are because I don't know the proper terms for those parts.

What could cause the rpms to surge but have a loss of power at the prop? Is there some type of clutch in this motor?

 

[Barnacle_Bill]

Re: 1998 Yamaha 115 hp 2 stroke - rpms rev up, but loss of power

It sounds like you have a spun prop. It can be re-hubbed and made as good as new. You can verify this by putting adjacent marks on the inner and outer hub. Then take it for another spin and check the marks to see if they are still lined up. Or take it to a prop shop and have them check it.